umm when you say clone do you mean you put a new drive in to replace the old one, and if so did it occur you may have different drive geometries?
just a wild thought.
heres the grub manual
stage 2 error 6 is from source above
6 : Mismatched or corrupt version of stage1/stage2
This error is returned if the install command points to incompatible or corrupt versions of the stage1 or stage2. It can't detect corruption in general, but this is a sanity check on the version numbers, which should be correct.
stage 1 error 6 is from source above
allegedly the same error but I like this one
The location of the stage2 or stage1.5 is not in the portion of the disk supported directly by the BIOS read calls. This could occur because the BIOS translated geometry has been changed by the user or the disk is moved to another machine or controller after installation, or GRUB was not installed using itself (if it was, the Stage 2 version of this error would have been seen during that process and it would not have completed the install).
Resolution I assume you just want to use images on a new drive?
so re-run grub but not with a recheck command
eg use grub-install /dev/hda
if that fails open a terminal and type su to get root password
once prompt changes to root
type grub and you enter the (bash like) grub editor
type each line and press enter
assume you want mbr install
grub> root (hd0)
grub > setup (hd0)
grub > boot
The last command does NOT cause reboot then you close the terminal and test.
If all works make a new boot floppy please